It is proposed to synthesize a large number of subpeptides of streptococcal M protein, E. coli type 1 fimbrlae, collagens and myelin basic protein in order to determine the structure-function relationships of these biologically active protein molecules. For this purpose an automated peptide synthesizer and HPLC system is needed in order that we may synthesize the appropriate peptide fragments and maintain the stringent quality controls necessary to complete these studies in a timely fashion. The synthetic peptides will be studied by immunological, biochemical and biological methods employing rabbits, rats, and mice as test animals. The delineation of the active regions of these protein molecules may shed light on structure-function relationships that are important in the pathogenesis of bacterial infections, collagen-vascular diseases and multiple sclerosis. The identification of the smallest peptide of strep tococcal M protein needed to evoke protective immunity would permit the elimination from rheumatic fever vaccines of unneeded portions of the M protein molecule that may harbor potentially harmful tissue cross-reactive antigenic determinants.